New Tool for Studying Synapse Biology

Neuroscience currently requires the use of antibodies to study synaptic proteins, where antibody binding is used as a correlate to define the presence, plasticity, and regulation of synapses. This study proposes a new, more general method. 

Seeing is believing, but tools are required to discover the hidden wonders of nature. For neuroscientists, antibodies against a specific synaptic protein help to “mark” synapse location within the brain, and coupling to fluorescent dyes allows high-resolution visualization under powerful microscopes. Such detection methods have aided our current understanding of the brain and principles underlying neuronal communication and synaptic plasticity that govern all aspects of our conscious existence. 

We have developed new tools, a class of synthetic protein binders called DARPins (or Designed Ankyrin Repeat Proteins) to visualize gephyrin at GABA synapses. The protein gephyrin plays a role in modulating inhibitory synaptic transmission. Our tool(s) unlike the commercial antibody are not biased towards a specific structural conformation of gephyrin, or its phosphorylation status. DARPins offer several advantages over classical antibodies due to their small size, low-cost production, bioengineering possibilities and intracellular expression. 

Reference: Campbell, B.F.N., Dittmann, A., Dreier, B., Plückthun, A., & Tyagarajan, S.K. A DARP in-based molecular toolset to probe gephyrin and inhibitory synapse biology. Elife (2022).

Caption: DARPin anti-gephyrin binders (magenta) label inhibitory postsynaptic sites along the Axon-initial-segment (yellow). In the CA1 pyramidal cell layer DAPI nuclear staining (Cyan).